The present invention relates to the field of engines having turbochargers. More particularly, the invention relates to an actuator for the waste gate valve of a turbocharger. This actuator mounts directly on the pressurized outlet of the turbocharger so that it can sense a pressure signal from inside the turbocharger outlet without relying on external hoses.
Waste gate valve actuators are generally known in the automotive engine art. Conventional actuators have a cap with a hollow stem protruding therefrom. One end of a flexible hose is connected to the stem and the other end is routed to a pressure input source, typically somewhere near the pressurized outlet of the turbocharger. The flexible hose is subjected to extreme temperatures and humidity, vibration, chemical corrosion, and a variety of other harsh environmental factors present in a turbocharged engine. Stainless steel braided hoses and the like are designed to be resistant to these factors, but are expensive considering they still have a limited life. The hose assembly costs more than the actuator in some cases. Furthermore, the connections at either end of the hose may sometimes leak and thereby decrease the performance of the turbocharged engine.
A separate bracket is typically provided to mount the actuator close to both the waste gate and the pressurized outlet of the turbocharger. As an additional component, the bracket increases the cost of manufacturing and assembling the actuator. The manufacturer must set the position of the bracket and the pre-formed hole in the actuator rod (for connecting the actuator to the waste gate valve) on a test stand at a given set pressure before shipping the actuator to the engine or turbocharger manufacturer. The set pressure corresponds to an idling condition of the engine. Sometimes the actual conditions encountered upon installation do not match the theoretical or presumed conditions used to establish the setting. Thus, undesirable variances in expected performance can result.
Tampering has been a troublesome and recurrent issue for conventional actuators with brackets and hoses. Some users have installed a clamp or an orifice in the hose to restrict the flow. This increases the boost pressure of the turbocharger. Others have installed spacers or shims around the bracket, pre-loading the actuator spring to alter the boost pressure. If the boost pressure is increased too much, the engine can be damaged.
Therefore, a primary objective of the present invention is the provision of an improved actuator for the waste gate valve of a turbocharger.
Another objective of the present invention is the provision of a hoseless actuator.
Another objective of the present invention is the provision of an actuator with integral means for mounting and fluidly connecting the actuator to the pressurized outlet of the turbocharger and locating the rod with respect to the waste gate, thereby eliminating the need for a separate mounting bracket.
Another objective of the present invention is the provision of an actuator which directly and accurately senses the pressure within the pressurized outlet of the turbocharger.
Another objective of the present invention is the provision of an actuator which reduces the opportunities for tampering.
Another objective of the present invention is the provision of an actuator which reduces the number of components of the installed actuator.
Another objective of the present invention is the provision of an actuator with an actuator rod that has a punch-set hole therein for accurately connecting the actuator to the waste gate valve.
Another objective of the present invention is the provision of means for making fine tuning adjustments in the effective length of the actuator rod and thereby fine tuning the boost pressure of the turbocharger.
Another objective of the present invention is the provision of an actuator which simplifies the assembly and test process.
Another objective of the present invention is the provision of an actuator which is economical to produce, durable, and reliable in use.
These and other objectives will be apparent from the drawings in view of the description and the claims which follow.